60 BtfLLETlN- 1090, U. S, DEPAP.TMEXT OF AGEICULTURE. 



Table 8. — Data on the fertility of the different inbred families , 1911 to 1915. 



Tam- 



Size of litter. 



Num- 

 ber of 



Num- 

 ber of 

 litters. 



Num- 

 ber of 

 yoimg. 



Aver- 

 age 

 size of 

 litter. 



Litters 



Young 



iiy- 



1 

 1 1 2 



3 



4 



5 



6 



7 



mating- 

 years. 



year. ' year. 



1 



16 

 42 

 19 

 49 

 26 

 17 

 42 

 12 



11 



97 

 30 

 67 

 46 

 38 

 96 

 21 

 2 

 117 

 72 



as 



61 

 61 

 47 

 55 

 39 



107 

 31 

 90 



107 

 45 

 91 



7 

 83 

 33 

 70 

 58 

 54 



134 

 26 

 1 

 72 

 46 

 41 

 52 

 28 

 43 

 39 

 52 

 84 

 22 

 97 

 88 

 59 



110 











12.6 

 64.7 

 25.9 

 67.6 

 55.2 

 53.8 

 100.7 

 25.9 

 1.2 

 88.3 

 51.8 

 37. 5 

 51.2 

 41.2 



34 

 246 



94 

 234 

 172 

 155 

 350 



66 

 3 



59 

 589 

 235 

 605 

 477 

 450 

 966 

 160 

 7 



1.74 

 2.39 

 2.50 

 2.58 

 2.77 

 2.90 

 2.76 

 2.42 



2.70 ' 4.68 



2.... 



16 

 6 

 33 

 30 

 36 

 63 

 7 



8 

 4 



11 

 7 

 9 



12 







3.80 9.10 



3.... 



7.... 



9.... 

 11.... 

 13.... 

 14 



1 

 3 

 5 

 1 

 3 



1 

 1 



3.63 

 3.46 

 3.12 

 2.88 

 3.48 

 2.55 



9.07 

 8.95 

 8.64 

 8.36 

 9.59 

 6.18 



15 











17 



18.... 

 19.... 

 20.... 

 21.... 



71 

 32 

 24 

 27 

 49 

 41 

 49 

 33 

 50 

 20 

 49 

 50 

 25 

 37 



38 

 23 

 23 

 15 

 8 

 14 

 15 

 28 

 26 

 13 

 64 

 42 

 21 

 44 



6 

 6 

 5 

 6 

 2 

 6 

 4 

 8 

 6 

 2 



15 

 6 

 6 



14 



1 

 2 

 3 



1 

 1 



"'i' 



306 716 

 182 i 455 

 131 352 

 162 402 

 148 297 

 151 350 



2.34 

 2.50 

 2.69 

 2.48 

 2.01 

 2.32 

 2.23 

 2.72 

 2.39 

 2.39 

 2.81 

 2.51 

 2.71 

 2.70 



3.47 

 3.51 

 3.49 

 3.16 

 3.59 

 3.80 

 3.54 

 2.90 

 3.47 

 3.07 

 3.73 

 3.44 

 2.46 

 3.41 



8.11 

 8.78 

 9.39 

 7.85 

 7.21 



23 







39.7 



8.82 



24.... 

 31.... 

 32.... 

 34 



..... 



1 



1 



46.1 

 56.9 

 78.9 

 28.7 

 87.2 

 86.1 

 62.6 

 87.0 



163 

 165 

 274 

 88 

 325 

 296 

 154 

 297 



363 

 449 

 656 

 210 

 912 

 744 

 418 

 802 



7.87 

 7.89 

 8.31 

 7.32 



35.... 

 36.... 

 38.... 

 39.... 



9 

 3 

 2 



1 

 ..... 



10.48 

 8.64 

 6.68 

 9.22 



Table 9. — The percentage born alive in the different inbred families. 



[The average in litters of each size and an index (litters of 1, 2, 3, and 4, weighted 1, 3, 4, and 2 respec- 

 tively), 1906 to 1910 and 1911 to 1915.] 







Size of litter, 1906-1910. 









Size of Utter, 1911-1915. 







Fam- 















Index. 











In- 



ily. 



























dex. 





1 



2 



3 



4 







6 





1 



2 



3 



4 







6 







Per 



Per 



Per 



Per 



Per 



Per 





Per 



Per 



Per 



Per 



Per 



Per 







c't. 



c't. 



c't. 



c't. 



c't. 



c't. 





c't. 



c't. 



c't. 



c't. 



c't. 



c't. 





1 



100.0 

 72.7 



76.9 

 82.5 



95.6 



88.1 



91.7 

 75.0 



100.0 

 94.3 



"'si's' 



89.7 

 82.3 



68.8 

 81.0 



95.5 

 90.2 



85.7 

 84.3 









85.9 



2.... 



76.6 



72.5 





84.2 



3.... 



76.9 



79.3 



83.7 



81.0 



95.0 



43.3 



81.2 



84.2 



83.3 



82.8 



50.0 



20.0 



00.0 



76.5 



7.... 



85.7 



85.1 



87.7 



77.0 



70.9 



50.0 



84.6 



81.6 



83.6 



81.4 



83.3 



72.7 



61.1 



82.5 



9.... 



84.6 



90.5 



84.8 



81.7 



85.0 



94.4 



85.9 



80.8 



84.8 



78.7 



a3. 3 



77.2 



50.0 



81.7 



11.... 



70.6 



90.2 



88.2 



84.4 



78.1 



63.3 



86.3 



76.5 



89.5 



88.3 



66.7 



48.9 



83.3 



83.2 



13.... 



79.0 



88.7 



88.5 



88.2 



86.0 



73.3 



87.6 



90.5 



87.5 



89.8 



85.3 



78.3 



94.4 



88.3 



14 . 



84.2 

 83.3 

 96.0 



80.5 

 78.6 

 95.2 



87.0 

 77.3 

 92.5 



82.4 

 78.1 

 92.1 



82.2 

 00.0 

 95.7 



33.3 



"ei.'i' 



83.9 

 7S.5 

 93.6 



8.3.3 

 "83." i' 



90.5 

 50.0 

 93.6 



76.9 

 66.7 



89.4 



67.9 







79.8 



15 









17.... 



82.9 



50.0 



83.3 



88.7 



18.... 



85.7 



90.3 



96.8 



95.8 



77.2 



90.0 



93.5 



75.0 



90.3 



92.0 



87.0 



53.3 



33.3 



88.8 



19 



90.9 



77.3 



87.9 



85.0 



92.0 





84.4 



1 91.7 



94.3 



77.2 



60.9 



80.0 



61.1 



80.5 



20.... 



85.0 



Si. 3 



85.4 



86.1 



90.0 



61.1 



85.2 



85.2 



35. 2 



89.1 



93.3 



83.3 





88.4 



21.... 



100.0 



88.0 



91.3 



94.4 



70.0 





91.8 



75. 5 



82.8 



85.7 



71.0 



10.0 





81.1 



23.... 



81.8 



96.4 



93.8 



95.5 



88.6 



66.7 



93.7 



80.5 



87.2 



93.8 



92.9 



90.0 





93. 3 



24.... 



87.0 



90.0 



89.3 



85.0 



78.2 



91.7 



88.4 



67.4 



75. 5 



82.9 



78.3 



40.0 





78.2 



31 ... . 



94.7 



%.7 



93.5 



93.8 



71.4 



41.7 



94.6 



66.7 



89.8 



78.2 



91.1 



95.0 



83.3 



83.1 



32.... 



95 4 



92.7 



90.6 



84.9 



72.2 



66.7 



90.6 



94.0 



85. 5 



89.7 



71.2 



56.7 



16.7 



85.2 



34.... 



50.0 



95.0 



93.3 



93.8 



75.0 





89.6 



75.0 



90.3 



90.9 



84.6 



40.0 





87.9 



35.... 



82,6 



9S.8 



93.3 



75.0 



60.0 



70.0 



90.2 



71.4 



88.9 



91.7 



83.2 



64.0 



46.2 



87.1 



36.... 



93.3 



94.3 



86.9 



78.0 



81.9 



90.0 



8«.0 



92.0 



91.6 



87.9 



73.2 



60.0 



55.6 



86.5 



38.... 



93.3 



93.6 



97.0 



84.5 



86.7 



83.3 



93.1 



88.0 



93.3 



92.7 



77.4 



53.3 



50.0 



89.4 



39.... 



90.9 



94.8 



84.3 



85.7 



0.0 



0.0 



88.4 



94.6 



94.0 



91.8 



85.8 



64.3 





91.5 



